Cloaca/cloacal

A separate, more complex group of anomalies is formed by the cloacal malformations, in which the urinary, genital and intestinal tracts converge to form a common channel with a single perineal orifice, i.e. the cloaca. These malformations are found exclusively in phenotypic females. 

Female brown tree snakes release cloacal secretions to inhibit male courtship (Greene and Mason, 2003). Female brown tree snakes are particularly active in the process of courtship compared to reports for other snakes (Greene and Mason, 2000). Females display overt courtship behaviors that appear to solicit courtship from males and may represent mechanisms to asses to quality of potential mates (Greene and Mason, 2000). Also, females lift their tails, gape their cloacae, and deposit secretions during courtship to which males respond by ceasing courtship activity (Greene and Mason,... 

Two attempts have been made to identify the source of the pheromones used in territorial communication by salamanders. The first was by Simon and Madison (1984), using experimental procedure (4) and Plethodon cinereus. They provided each male salamander with a choice of two substrates, each marked with either fecal pellets or cloacal washes. On one side, the pellets (or washes) were the test animal s own on the other side, the pellets (or washes) were from a conspecific. None of the salamanders had prior experience with each other. For both pellets and washes, salamanders significantly chose their own marked substrates over those of conspecifics. This was the first indication that fecal pellets are used to place pheromones in territories. In addition, the data from cloacal washes suggest that pheromones are produced by glands in or around the cloaca, and are not a by-product of the chemical composition of the feces per se. 

Dunson used hatchling slider turtles (Pseudemys scripta) in sodium flux studies. The turtles were placed in a sodium chloride solution containing Na, and the body burden was determined with a scintillation counting system for the turtles with the cloaca open and closed. On the basis of these studies on intact animals and of in vitro membrane studies, it was concluded that transport was localized in the cloacal and oral regions. 

Development of the external genital organs, the urethra, and the anus involve transformation processes of the internal and external cloaca, which are separated by the cloacal membrane in a transverse plane (Stephens 1983a Nievelstein et al. 1998). At 4 weeks the internal cloaca is a single chamber, into which issue the large intestine, the hindgut, the allantois, and the wolffian ducts. 

Definitive correction of the cloaca can now be performed between the ages of 6 and 24 months (Hendren 1998), and the prognosis of infants with cloacal malformation has improved significantly during recent years due to surgical repair techniques pioneered by Hendren. 

The rectum frequently fails to opacify after the injection of contrast material into the cloaca. In patients who have already had a colostomy, contrast material can be directly injected into the distal limb of the colostomy prior to retrograde cloacal injection. This technique regularly demonstrates the level of rectal occlusion and the presence of conunu-nication between other pelvic structures, making further cloacal injections unnecessary (Fig. 7.23). Most commonly, a balloon catheter is used to inject contrast material under moderate pressure to dem-... 

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